Many medical procedures require the removal of bodily fluids such as: saliva and blood during dental procedures, blood and loose tissue during surgery, and vomit, mucous, and saliva during airway management. Bodily fluids may be extracted using a vacuum source, such as a pump, aspirator, etc. A tube or wand coupled to the vacuum source may be directed to the fluid source for collecting the bodily fluids. These fluids may be trapped in a collection vessel so that germs, diseases, and other biological hazards are not transmitted to the environment or vacuum pump. Together, the vacuum source and collection vessel may commonly be referred to as a medical suction device. In some examples, as shown in U.S. Pat. No. 4,930,997, medical suction devices may also include a filter for ensuring that only air passes through the vacuum source to the environment.
However, conventional medical suction devices rely on gravity and buoyant forces to collect liquids in the collection vessel, and seal the collection vessel when it becomes full. As such, traditional collection vessels must be vertically orientated with respect to gravity in order to be properly sealed. In many cases, if the collection vessel is overturned or disoriented, liquids may either prematurely block a safety check valve stopping suction or leak out from the collection vessel, resulting in tedious clean-up procedures and potential disease transmission. Given the nature of emergency responses under a wide variety of field conditions, the probability that the collection vessel is tilted during aspiration is significant. As such, a risk of disease transmission exists with conventional medical suction devices.
In microgravity environments, aspiration poses additional challenges and medical risks. For example, separating liquids from gases and allowing liquid capture within the collection vessel may be difficult. Although centripetal forces may be used to coalesce aspirated liquids and particles from a gas containing stream, trapping the liquids from this stream requires a more complex phase separator that must be incorporated in the collection system.
Another problem with microgravity suction is the manner in which fluids flow to the point of suction from the fluid source. While fluids immediately adjacent to the opening of the tube/wand will be drawn into the tube, contact between the wand and the liquids not immediately adjacent to the wand is maintained only by surface tension forces of the liquids. If the surface tension forces are not sufficient to hold the liquids together, a void may form around the wand during aspiration. As a result, suction may draw only gasses into the device. Thus, in order to collect more liquids from a surface, the vacuum wand must be repositioned on the wetted surface. Because medical suction is often performed on areas with fragile body tissues, scraping a wand, which is typically made of hard plastic, over the relevant surfaces, poses significant risks to a patient.
A substantial amount of air may be drawn into the aspiration system along with liquid and/or solid material when the wand is being repositioned. Further, air may be drawn into the aspiration system during extraction of bodily fluids due to an inability to generate a complete seal between the wand and a complex or fragile surface. Excess gas may prematurely fill the collection vessel, limiting the storage capacity of the vessel, and increasing the risk of leaks.
The inventors herein have recognized the issues described above, and have devised a system for addressing the issues. In particular, a cartridge which may be included in a medical suction device is disclosed herein which comprises a removably coupled bag that may be inserted and removed from the cartridge, for filtering fluids flowing through the cartridge and/or medical suction device.
In one example, a cartridge may include a porous filler material loaded with absorption granules for absorbing liquids, and a hydrophobic liquid barrier which may be permeable only to one or more of air and gasses, and positioned within the cartridge so that fluids in the cartridge may not exit the cartridge without flowing through the barrier. The cartridge may further comprise a disposable bag which is removably coupled to the cartridge, and comprises the porous filler material and the hydrophobic liquid barrier. Additionally or alternatively, the cartridge may comprise a rigid housing, the rigid housing including the porous filler material and the hydrophobic liquid barrier. In some examples, the disposable bag may be included within the rigid housing.
In further examples, the cartridge may include one or more or each of an inlet tube physically coupled to an inlet end of the bag, and an outlet tube. In examples where the bag is flexible, the outlet tube may be physically coupled on one end to an outlet end of rigid housing, and on an opposite end to the vacuum source, so that fluids in the cartridge may flow from the inlet tube, to the disposable bag, and then only gasses may exit the bag to the vacuum source via the outlet tube. However, in examples where the bag is rigid, the outlet tube may be directly physically coupled to the bag. In such examples, the rigid housing may not be included in the cartridge. Thus, the cartridge may comprise only the bag, which may be coupled on one end to the inlet tube, and on the opposite end to the outlet tube. In still further examples of the cartridge, the porous filler material may comprise one or more or each of a reticulated foam with approximately 20 pores per square inch. In other examples of the cartridge, the hydrophobic liquid barrier may comprise porous polytetrafluoroethylenes or other porous hydrophobic membranes.
In other representations, the absorption granules may comprise sodium polyacrylate. A density of the absorption granules in the filler material may increase with increasing radial deflection from a central axis of the bag. In still further examples, the bag may further comprise one or more or each of perforated walls and sealed walls, which may be arranged within the bag in an alternating order and orientated parallel to one another and perpendicular to a flow direction of fluids in the bag, and which may be spaced from one another such that passages are formed between the walls. The perforated walls may be in sealing contact with the bag and may comprise a central opening so that fluids flowing through the bag may flow through the central opening and may not flow around the perforated walls, and where outer edges of the sealed walls may not be in sealing contact with the bag, so that fluids flowing through the bag may flow around and not through the sealed walls. Said another way, a gap may be formed between outer edges along a circumference of the sealed walls and interior surfaces of the bag.
In this way, filtration and removal of liquids and infectious agents from a fluid source may be improved by providing a removably coupled bag in a cartridge with a liquid barrier that prevents liquids from exiting the bag, and traps liquids and potentially infectious agents within the bag. Further, the filtration and absorption efficiency of the cartridge may be maintained despite manipulation of the orientation of the cartridge. Since absorption granules and filler material may be included in the cartridge and may be evenly distributed in the cartridge, absorption and therefore filtration of the bag may be relatively the same regardless of the orientation of the cartridge. Additionally, sanitation levels may be increased and exposure to the liquids may be reduced since the bag may be removably coupled to the cartridge. Thus, the bag may be inserted and attached, or decoupled and removed from the cartridge to provide increased ease of disposal of the liquids.
The above summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the subject matter, nor is it intended to be used to limit the scope of the subject matter. Furthermore, the subject matter is not limited to implementations that solve any or all of the disadvantages noted above or in any part of this disclosure.